1. Field of the Invention
The present invention relates to the field of display technology, and more particular to a light-emitting diode (LED).
2. The Related Arts
Light-emitting diode (LED) is a semiconductor device that converts electrical current into light. Wavelength of light emitting from a light-emitting diode varies according to the semiconductor material involved, and, more specifically speaking, is varying according to the band gap of the semiconductor material involved. The LED is commonly used as a light source for displays, vehicles, and other applications of illumination. In the LEDs, the amount of heat generated by the light-emitting diodes would directly affect lighting performance and lifespan of a light-emitting diode module, and thus affects the service life of backlighting of a mobile phone display screen or a television display screen. If the heat generated by the light-emitting diode is long kept in the light-emitting diode, then, consequently, dislocation and mismatch would occur in the crystalline structure that makes the light-emitting diode so as to shorten the service life of the light-emitting diode.
Light-emitting diodes that are currently available are classified as a vertical structure and a non-vertical structure (planar structure), in which for a light-emitting diode of the non-vertical structure, an n electrode and a p electrode are respectively located on the same side of an emissive layer, while for a light-emitting diode of the vertical structure, the n electrode and the p electrode are respectively located on upper and lower sides of the emissive layer. Due to constraints on the performance of an electrode transportation layer of a known light-emitting diode, an electrical current flowing between the n electrode and the electron transportation layer does not flow smoothly into the emissive layer, and consequently, the lighting efficiency of the light-emitting diode is affected and heat cannot be well dissipated through the electron transportation layer, leading to an excessively high temperature of the emissive layer. Particularly, for a light-emitting diode of the non-vertical structure, a sapphire substrate provided on one side of a hole transportation layer is of poor thermal conductivity so that, in consideration of heat dissipation, it is necessary for an even larger amount of heat to be dissipated through the electron transportation layer. Thus, upgrading the performance of the electron transportation layer would be of vital influence on the lighting performance and service life of the light-emitting diode.
Graphene is a two-dimensional crystal formed of carbon atoms arranged in a honeycomb form, showing various advantages including high transmission rate, high thermal conductivity, high electron mobility, and low electrical resistivity. The excellent properties make graphene, as well as devices associated therewith, a hot spot of study and research in the fields of physics, chemistry, biology, and material science. Various devices that involve graphene as basic functional units have been made up to date, including field-effect transistors, solar cells, nanometer electrical machines, and transducers.